Large pipeline compressor engines and similar machines are conventionally installed and supported on sub-surface epoxy-covered concrete foundations, using leveling support assemblies about each anchor bolt which reaches downward into the foundation. These leveling assemblies conventionally consist of chocks on steel sole plates grouted in place on the epoxy-covered foundation with removable steel chocks interposed between the machine base or bedplate and the sole plates. Both the sole plates and chocks conventionally have a vertical slot, to fit around an anchor bolt securing the machine base to the foundation.
The term "sole plate" designates the basic leveling member which supports a shimmed chock upon which the machine base or bedplate rests at several points of support. Each sole plate is a somewhat elongated steel plate which has at each end a heavy lift bolt. With such machine in position and temporarily supported by screw jacks, each sole plate is positioned with its lift bolt tips rested on small circular plates positioned on a sub-surface epoxy-topped concrete foundation. With chocks (thickened with 0.035 inches of shims) temporarily in place on the sole plates, they are brought up to the machine base by turning the lift bolts. Epoxy grout is then poured onto the foundation beneath the sole plates and up to the level of their upper surfaces. When the grout has hardened the lift bolts are turned to raise their tips slightly.
The load may then be transferred from the screw jacks by screwing the lift bolts upward so that the bolt heads (or spacers placed temporarily on them) rise up against the undersurface of the machine base. After removal of the screw jacks the lift bolts may then be lowered so the load rests on the chocks.
As a final step for achieving precise leveling alignment, the lift bolts at selected support points are again screwed upward so their heads (or spacers) bear upward against the machine base, raising the weight off the chocks. These chocks may then be removed for addition or subtraction of shims. With the chock thickness adjusted, the chocks are replaced and the lift bolts are again lowered. This transfers the machine weight again to the chocks.
Such conventional steel support assemblies have been attended by serious service problems resulting from heat and vibration. Heat from such engines, approximating the oil temperature of 140-160 degrees F., is conducted from the engine frame through the steel chocks and sole plates to the poured-in epoxy grout and the epoxy covering of the concrete foundation. At such temperatures heat impairs the strength of the grout; the sole plates may then break loose from the grout under the vibrations of the engine. Further, when engines are supported on steel chocks or shims, their vibrations may cause the engine support surfaces to wear away by "fretting". Restoration work on such support surfaces, as well as grout restoration, may be extremely expensive.
Some experimental efforts, recently made, substitute both sole plates and chocks made of mat-reinforced plastic material. These efforts did not reach the stage of effective commercialization, because the plastic soleplates were too flexible in bending to withstand the imposed loads when applied or reacted through the lift bolts, either on installation or on subsequent leveling operations. For example to install them in regrouting operations, it was ordinarily necessary to make extensive temporary installations of screw jacks closely spaced under the machine base.